arXiv subjects

Yajiang Hao

Publications and source records attributed to Yajiang Hao.

At least 19 recordsLinked to original sources

arXiv2026

Emulation of the dynamics of bound electron exposed to strong oscillatory laser field with Bose-Einstein Condensates

This paper employs a Bose-Einstein condensates to simulate the dynamical response of bound electrons in a strongly oscillating pulsed laser field. We investigate the excitation dynamics of Bose-Einstein condensates with repulsive interaction confined in a potential well with finite depth and width driven by a strong oscillatory pulse field. By numerically solving the Gross-Pitaevskii equation with Crank-Nicolson method and split operator method, we obtain the time-dependent wavefunction and therefore the evolution of density distribution in real space and that in momentum space, and the occupation distribution in energy space. It is shown that cold atoms with weak interaction oscillate as a whole body in a finite space when the amplitude of pulse drive is not strong enough. During the evolution atoms occupy the bound states with larger probability. Increasing the driving strength or atomic interactions promotes the excitation of atoms into continuum states and their diffusion out of the potential well, leading to complex structures or even interference-like patterns in the momentum distribution. The number of cycles in the pulse envelope plays a crucial role in the dynamical behavior: High-frequency driving can suppress diffusion and maintain localization. Furthermore, repulsive atomic interactions can enhance high-harmonic generation yields by several orders of magnitude. This study offers a new perspective for quantum simulations of ultrafast dynamics in strong fields and reveals the regulatory role of interactions in condensates on non-equilibrium dynamical processes.

cond-mat.quant-gas↗

arXiv2025

Spatiotemporal scales of dynamical quantum phase transitions in the Bose-Hubbard model

We investigate the spatial and temporal scales of dynamical quantum phase transitions in the one-dimensional Bose-Hubbard model in the strong interaction limit. Using Jordan-Wigner transformation, we obtain the time-dependent wavefunction and therefore the subsystem Loschmidt echo, and systematically investigate how its properties vary with subsystem size. It is found that when the subsystem is sufficiently large, it exhibits logarithmic divergence identical to that of the full system Loschmidt echo, yielding a critical exponent of zero. We also obtain the required subsystem size and temporal resolution for detecting dynamical quantum phase transitions using the subsystem Loschmidt echo. It is expected that the present results provide a reliable foundation for further experimental investigations.

cond-mat.quant-gas↗

arXiv2025

Critical Exponent of Dynamical Quantum Phase Transition in One-Dimensional Bose-Hubbard Model in the Strong Interacting Limit

We analytically investigated the dynamical quantum phase transitions in the Bose-Hubbard model using the Loschmidt echo as an observable, revealing that after a quench, the global Loschmidt echo exhibits cusp singularities with a logarithmically divergent rate function near criticality and a critical exponent of zero. Through extensive calculations across various system sizes and initial states, we have demonstrated that in the strongly interacting regime, the critical singularity of dynamical quantum phase transitions exhibits consistency across different model details and initial product states (charge-density wave states). Moreover, we find that modifying the harmonic potential well not only preserves the phase transition but also enables precise control over the transition timing.

cond-mat.quant-gas↗

arXiv2024

The dynamics of Tonks-Girardeau gas excited by a pulse drive

In this paper we study the dynamics of Tonks-Girardeau (TG) gases in a harmonic potential driven by Gaussian pulse, which is a correspondence of the excitation dynamics of electrons in matters driven by ultrashort laser pulse. The evolving dynamics of TG gas are obtained with Bose-Fermi mapping method combined with the numerical techniques. We calculate the evolving dynamics of occupation distribution of single-particle energy levels, density distribution and momentum distribution of the system. It is shown that the system arrived at a dynamically stable state at the end of driving. At high-frequency regime TG gases return back to ground state while at low-frequency regime the population inversion exhibits and all atoms occupy high levels.

cond-mat.quant-gas↗

arXiv2023

Ground state of Tonks-Girardeau gas under density-dependent gauge potential in a one dimensional harmonic potential

In the present paper we investigate the ground state of Tonks-Girardeau gas under density-dependent gauge potential. With Bose-Fermi mapping method we obtain the exact ground state wavefunction for the system confined in a harmonic potential. Based on the ground state wavefunction, the reduced one body density matrix (ROBDM), natural orbitals and their occupations, and the momentum distributions are obtained. Compared with the case without gauge potential, the present wavefunction and ROBDM have additional phase factors induced by gauge potential. The momentum distribution is the convolution of that without gauge potential to the Fourier transformation of definite integral of gauge potential. It is shown that because of the density-dependent gauge potential the peak of momentum distributions deviate from zero momentum and the Bose gas take finite total momentum. In particular the momentum distribution is no longer symmetric although the total momentum can become zero by adding a constant to the gauge potential.

cond-mat.quant-gas↗

arXiv2022

Non-Hermitian skin effect in one-dimensional interacting Bose gas

Non-Hermitian skin effect (NHSE) is a unique feature studied extensively in non-interacting non-Hermitian systems. In this work, we extend the NHSE originally discovered in non-interacting systems to interacting many-body systems by investigating an exactly solvable non-Hermitian model, i.e., the prototypical Lieb-Liniger Bose gas with imaginary vector potential. We show that this non-Hermitian many-body model can also be exactly solved through Bethe ansatz. By solving the Bethe ansatz equations accurately, the explicit eigenfunction is obtained, and the model's density profiles and momentum distributions are calculated to characterize the NHSE quantitatively. We find that the NHSE is gradually suppressed on the repulsive side but does not vanish as the repulsive interaction strength increases. On the attractive side, the NSHE for bound-state solutions is enhanced as interaction strength grows. In contrast, for the scattering state the NHSE shows a non-monotonic behavior in the attractive side. Our work provides the first example of the NHSE in exactly solvable many-body systems, and we envision that it can be extended to other non-Hermitian many-body systems, especially to integrable models.

cond-mat.quant-gas↗

arXiv2022

$n$-body Correlation of Tonks-Girardeau Gas

For the well-known exponential complexity it is a giant challenge to calculate the correlation function for general many-body wave function. We investigate the ground state $n$th-order correlation functions of the Tonks-Girardeau (TG) gases. Basing on the wavefunction of free fermions and Bose-Fermi mapping method we obtain the exact ground state wavefunction of TG gases. Utilizing the properties of Vandermonde determinant and Toeplitz matrix, the $n$th-order correlation function is formulated as $(N-n)$-order Toeplitz determinant, whose element is the integral dependent on 2$(N-n)$ sign functions and can be computed analytically. By reducing the integral on domain $[0,2π]$ into the summation of the integral on several independent domains, we obtain the explicit form of the Toeplitz matrix element ultimately. As the applications we deduce the concise formula of the reduced two-body density matrix and discuss its properties. The corresponding natural orbitals and their occupation distribution are plotted. Furthermore, we give a concise formula of the reduced three-body density matrix and discuss its properties. It is shown that in the successive second measurements, atoms appear in the regions where atoms populate with the maximum probability in the first measurement.

cond-mat.quant-gas↗

arXiv2022

Quench Dynamics of Anyon Tonks-Girardeau Gases

We investigate the dynamical evolution of strongly interacting anyons confined in a weak harmonic trap using the exact anyon-fermion mapping method. The density profiles, momentum distribution, and the reduced one-body density matrix are obtained for different statistical parameters. The density profiles of anyons display the same behaviors irrespective of statistical parameter during the evolution. As the harmonic trap is turned off suddenly, the momentum distributions exhibit the symmetric fermion-like behaviour in the long time evolution. As the trap frequency is quenched, the momentum distribution exhibit an asymmetry breath mode during the evolution. The reduced one-body density matrix show the dynamical symmetry broken and reproduced behaviour.

cond-mat.quant-gas↗

arXiv2022

Correlation in Momentum Space of Tonks-Girardeau Gas

We investigate the correlation properties of the ground state of Tonks-Gigrardeal gases in the momentum space. With Bose-Fermi mapping method the exact ground state wavefunction in coordinate space can be obtained basing on the wavefunction of spin-polarized Fermions. By Fourier transformation we obtain the ground state wavefunction in momentum space, and therefore the momentum distribution, pair correlation and the reduced one-body density matrix (ROBDM) in momentum space. The ROBDM in momentum space is the Fourier transformation of the ROBDM in coordinate space and the pair correlation in momentun space is the Fourier transformation of the reduced two-body density matrix in coordinate space. The correlations in momentum space display larger values only in small momentum region and vanish in most other regions. The lowest natural orbital and occupation distribution are also obtained.

cond-mat.quant-gas↗

arXiv2019

Theoretical evidence for the sensitivity of charge-rearrangement-enhanced x-ray ionization to molecular size

It was recently discovered that molecular ionization at high x-ray intensity is enhanced, in comparison with that of isolated atoms, through a phenomenon called CREXIM (charge-rearrangement-enhanced x-ray ionization of molecules). X-ray absorption selectively ionizes heavy atoms within molecules, triggering electron transfer from neighboring atoms to the heavy atom sites and enabling further ionization there. The present theoretical study demonstrates that the CREXIM effect increases with the size of the molecule, as a consequence of increased intramolecular electron transfer from the larger molecular constituents attached to the heavy atoms. We compare x-ray multiphoton ionization dynamics of xenon, iodomethane, and iodobenzene after interacting with an intense x-ray pulse. Although their photoionization cross sections are similar, iodomethane and iodobenzene molecules are more ionized than xenon atoms. Moreover, we predict that the average total charge of iodobenzene is much larger than that of iodomethane, because of the large number of electrons in the benzene ring. The positive charges transferred from the iodine site to the benzene ring are redistributed such that the higher carbon charges are formed at the far end from the iodine site. Our first-principles calculations provide fundamental insights into the interaction of molecules with x-ray free-electron laser (XFEL) pulses. These insights need to be taken into account for interpreting and designing future XFEL experiments.

physics.chem-ph↗

arXiv2016

One-dimensional hard-core anyon gas in a harmonic trap at finite temperature

We investigate the strongly interacting hard-core anyon gases in a one dimensional harmonic potential at finite temperature by extending thermal Bose-Fermi mapping method to thermal anyon-ferimon mapping method. With thermal anyon-fermion mapping method we obtain the reduced one-body density matrix and therefore the momentum distribution for different statistical parameters and temperatures. At low temperature hard-core anyon gases exhibit the similar properties as those of ground state, which interpolate between Bose-like and Fermi-like continuously with the evolution of statistical properties. At high temperature hard-core anyon gases of different statistical properties display the same reduced one-body density matrix and momentum distribution as those of spin-polarized fermions. The Tan's contact of hard-core anyon gas at finite temperature is also evaluated, which take the simple relation with that of Tonks-Girardeau gas $C_b$ as $C=\frac12(1-cosχπ)C_b$.

cond-mat.quant-gas↗

arXiv2016

Ground State Properties of Anti-Ferromagnetic Spinor Bose gases in One Dimension

We investigate the ground state properties of anti-ferromagnetic spin-1 Bose gases in one dimensional harmonic potential from the weak repulsion regime to the strong repulsion regime. By diagonalizing the Hamiltonian in the Hilbert space composed of the lowest eigenstates of single particle and spin components, the ground state wavefunction and therefore the density distributions, magnetization distribution, one body density matrix, and momentum distribution for each components are obtained. It is shown that the spinor Bose gases of different magnetization exhibit the same total density profiles in the full interaction regime, which evolve from the single peak structure embodying the properties of Bose gases to the fermionized shell structure of spin-polarized fermions. But each components display different density profiles, and magnetic domains emerge in the strong interaction limit for $M=0.25$. In the strong interaction limit, one body density matrix and the momentum distributions exhibit the same behaviours as those of spin-polarized fermions. The fermionization of momentum distribution takes place, in contrast to the $δ$-function-like distribution of single component Bose gases in the full interaction region.

cond-mat.quant-gas↗

arXiv2016

Ground state properties of hard-core anyons in a harmonic potential

Using anyon-fermion mapping method, we investigate the ground state properties of hard-core anyons confined in a one-dimensional harmonic trap. The concise analytical formula of the reduced one-body density matrix are obtained. Basing on the formula, we evaluated the momentum distribution, the natural orbitals and their occupation distributions for different statistical parameters. The occupation and occupation fraction of the lowest natural orbital versus anyon number are also displayed. It is shown that the ground state properties of anyons interplay between Bosons and Fermions continuously. We can expect that the hard-core anyons of larger statistical parameter exhibit the similar properties to the hard-core Bosons although anyon system satisfy specific fractional statistics.

cond-mat.quant-gas↗

arXiv2016

Dynamics of spinor Bose-Einstein condensate subject to dissipation

We investigate the internal dynamics of the spinor Bose-Einstein Condensates subject to dissipation by solving the Lindblad master equation. It is shown that for the condensates without dissipation its dynamics always evolve along specific orbital in the phase space of ($n_0$, $θ$) and display three kinds of dynamical properties including Josephson-like oscillation, self-trapping-like oscillation and 'running phase'. In contrast, the condensates subject to dissipation will not evolve along the specific dynamical orbital. If component-1 and component-(-1) dissipate in different rates, the magnetization $m$ will not conserve and the system transits between different dynamical regions. The dynamical properties can be exhibited in the phase space of ($n_0$, $θ$, $m$).

cond-mat.quant-gas↗

arXiv2016

The weakening of fermionization of one dimensional spinor Bose gases induced by spin-exchange interaction

We investigate the ground state density distributions of anti-ferromagnetic spin-1 Bose gases in one dimensional harmonic potential in the full interacting regimes. The ground state is obtained by diagonalizing the Hamiltonian in the Hilbert space composed of the lowest eigenstates of noninteracting Bose gas and spin components. The study reveals that in the situation of weak spin-dependent interaction the total density profiles evolve from Gaussian-like distribution to a Fermi-like shell structure of $N$ peaks with the increasing of spin-independent interaction. While the increasing spin-exchange interaction always weaken the fermionization of density distribution such that the total density profiles show shell structure of less peaks and even show single peak structure in the limit of strong spin-exchange interaction. The weakening of fermionization results from the formation of composite atoms induced by spin-exchange interaction. It is also shown that phase separation occurs for the spinor Bose gas with weak spin-exchange interaction, meanwhile strong spin-independent interaction.

cond-mat.quant-gas↗

arXiv2015

The properties of Tonk-Girardeau Gas at Finite Temperature and Comparison with Polarized Free Fermions

In the present paper we investigate the Tonks-Girardeau gas confined in a harmonic trap at finite temperature with thermal Bose-Fermi mapping method. The pair distribution, density distribution, reduced one-body density matrix, the occupations number of natural orbitals, and momentum distribution are evaluated. In the whole temperature regime the pair distribution and density distribution exhibit the same properties as those of polarized free Fermions because both of them depend on the modulus of wavefunction rather than wavefunction. While the reduced one-body density matrix, the natural orbital occupation, momentum distribution, which depend on wavefunction, of Tonks gas displays Bose properties different from polarized free Fermions at low temperature. At high temperature we can not distinguish Tonks gas from the polarized free Fermi gas by all properties qualitatively.

cond-mat.quant-gas↗

arXiv2015

Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity

We present the implementation of an electronic-structure approach dedicated to ionization dynamics of molecules interacting with x-ray free-electron laser (XFEL) pulses. In our scheme, molecular orbitals for molecular core-hole states are represented by linear combination of numerical atomic orbitals that are solutions of corresponding atomic core-hole states. We demonstrate that our scheme efficiently calculates all possible multiple-hole configurations of molecules formed during XFEL pulses. The present method is suitable to investigate x-ray multiphoton multiple ionization dynamics and accompanying nuclear dynamics, providing essential information on the chemical dynamics relevant for high-intensity x-ray imaging.

physics.chem-ph↗

arXiv2013

Dynamics of double-well Bose-Einstein Condensates subject to external Gaussian white noise

Dynamical properties of the Bose-Einstein condensate in double-well potential subject to Gaussian white noise are investigated by numerically solving the time-dependent Gross-Pitaevskii equation. The Gaussian white noise is used to describe influence of the random environmental disturbance on the double-well condensate. Dynamical evolutions from three different initial states, the Josephson oscillation state, the running phase and $π$-mode macroscopic quantum self-trapping states are considered. It is shown that the system is rather robust with respect to the weak noise whose strength is small and change rate is high. If the evolution time is sufficiently long, the weak noise will finally drive the system to evolve from high energy states to low energy states, but in a manner rather different from the energy-dissipation effect. In presence of strong noise with either large strength or slow change rate, the double-well condensate may exhibit very irregular dynamical behaviors.

cond-mat.quant-gas↗